In partial or total minimally invasive (MIS) hip surgery, a surgeon operates through an incision of about 10 cm or less without imparting problematic anatomical forces or compromising component positioning. Conventionally, an open approach has utilized an incision of about 15-30 cm, leading to more tissue damage, more blood loss, more post-operative pain, a longer hospital stay, and a delayed return to work and other functional activities.
One downside to MIS hip surgery, however, is that conventional instruments can damage soft tissues when used through a small incision, and there is a risk of implanting components incorrectly, especially the acetabular component, which may inadvertently be anteverted or abducted, such that the hip joint is in an improper orientation and is “open” (overly anteverted) or “closed” (retroverted) too much. FIG. 1 is a series of images illustrating an example of a retroverted acetabular component (on the left) and an overly anteverted acetabular component (on the right).
Anteversion and abduction of the acetabular component are very difficult to judge intra-operatively, and are often done post-operatively using various computerized alignment measurement systems. Thus, the present invention provides systems and methods that utilize intra-operative fluoroscopy and/or intra-operative radiographs and visualizable guide lines to measure the anteversion or abduction of the acetabular component. The systems and methods of the present invention find particular applicability in a direct anterior (DA) approach to the hip, as well as other approaches, as will best be appreciated by those of ordinary skill in the art.